The present invention relates to digital media distribution. In particular, this invention relates to the distribution of licenses to access digital media content distributed over a computer network.
Digital media content, as opposed to analog media, is susceptible to infinite reproduction while maintaining intact the quality of each replica. As such, digital media content is easily distributed over computer networks, which provide a medium for low-cost delivery of content to consumers with legitimate rights to access the content. Unfortunately, computer networks also provide a medium for piracy, unauthorized use, and illegal distribution of digital media content. A well-recognized example of a computer network is the Internet. The Internet has revolutionized the media industry by providing content owners the ability to distribute media to the consumer in an effective and expedient fashion. Additionally, Internet-based distribution of media content benefits consumers in that they have at their fingertips a wide selection of digital media content that is immediately available. Unfortunately, the advent of the Internet has also accelerated the illicit duplication of copyright-protected digital content. Faster computer processors, affordable storage capacity, widespread Internet usage and the advent of peer-to-peer file sharing networks have not only allowed consumers to acquire and play media files legitimately, but also to share them with unauthorized consumers.
A leading solution to this problem is Digital Rights Management (“DRM”) technology. In broad terms, DRM is a media distribution scheme that permits content owners to securely distribute media content to consumers through the use of digital licenses. DRM differs from traditional methods of encrypted media distribution in that DRM technology allows a content owner to keep control of the number of times content decryption may occur, the time period during which content decryption is available, the user's ability to make copies or to transfer the media object to another device, and other aspects of the use of the media. Traditional methods of encrypted media distribution deliver the media file and lose control of the content once the file is decrypted.
Application of a typical DRM system involves a subscriber, a content owner, a content distributor, and a license server. A subscriber is generally the media consumer who through a client computer requests, obtains, and plays media content. The internal programming of the media player (e.g. Microsoft® Windows Media Player) requires the subscriber to have a valid license to play the media content if the media content is coded with such a requirement. A content owner is an entity with rights over any form of intangible property such as digital media content. Examples of content owners include media companies, record labels, filmmakers, and recording artists. Content distributors are media retailers who most often distribute media content through their Internet website by content streaming or content downloading. In some cases, the content owner will distribute its own content in which case it simultaneously serves as a content distributor. Finally, a license server is the server that receives license requests from the subscriber's media player and downloads digital licenses to authorized consumers. A digital license contains the necessary decryption key as well as business model rules (such as the number of times the media file can be played and the expiration period of the license), which can be set by the content distributor.
The usual flow of events for media distribution employing a DRM system starts with a content owner who encrypts its media content with a key and packages it with information such as the content ID and the license acquisition universal resource locator (“LAURL”). The content ID is the identifier of the media file. The LAURL is the URL that points to the license server and allows the subscriber's computer to acquire a license if one is needed (i.e., is not already present on the computer system). Once the content owner packages the media content, it may transfer the media content to the content distributor. At this point the digital media is ready for distribution. Using preferred business models, the content distributor markets the media content to subscribers. A consumer who has subscribed to the content will then go to the content distributor website and download or stream the packaged media file. Depending on the architecture of the DRM system, a license to the media may also be delivered to the user's device at this time. The consumer's computer stores the license for future use and the media player then uses the license to decrypt and play the media content. Later attempts to play the media content by the user will cause the user's computer to use the license stored in the consumer's computer. Access will be provided to the media content, allowing it to be played, according to the business rules specified in the license. If the consumer transfers the media content to another consumer or to another device, on the first attempt to play the media content on such a new device, the media player will request a license from the server addressed by the LAURL packaged with the media content (such a request is generally called a challenge). Once the challenge has been successfully met, the license server will generate and download a license to the requesting computer. The consumer's computer stores the license for future use and the media player then uses the license to decrypt and play the media content. Later attempts to play the content by the user will cause the user's computer to use the license stored in the consumer's computer. Access will be provided to the media content, allowing it to be played, according to the business rules specified in the license.
Consumer access to obtain the media content in the first place or to obtain a license via a challenge requires some method of authentication. Consumers are generally required to enter a username and password before gaining access to the content distributor's lists of media content and/or before downloading media content, or before downloading a new license requested via a challenge. For example, after the consumer subscribes with the content distributor, every time she wants to obtain a song from the content distributor's website she enters a username and password and the encrypted media content is delivered to her along with the license. Alternatively, if the license is not delivered with the media content, the consumer's player will request a license and before the license is delivered to the media player, the subscriber will be prompted for username and password. If the consumer is an authorized subscriber the digital license is delivered, which enables the player to decrypt and play the media.
The username-and-password paradigm, however, falls short in protecting network-distributed media and at the same time is unduly cumbersome for the user. The username-and-password paradigm falls short in protecting network distributed media, because a user name and password are easily shared between individuals. Accordingly, a single user who shares her usermame and password with multiple users can easily enable those multiple users to obtain free copies of the media and the license to decrypt the media. In the extreme, a single user can easily post a username and password on a bulletin board or other electronic location, thereby enabling an unlimited number of other users to obtain playable copies of the media, thus undermining completely the content distributor's ability to generate profit from distribution of the content. At the same time, the username-and-password paradigm is unduly cumbersome because, by definition, it requires the user to identify herself in some manner, when such information is irrelevant to the content distributor, who typically does not need or want to know the identity of each recipient of a single copy of a mass distributed media. Instead, the content distributor wants to receive one royalty for each usable copy of the media distributed irrespective of who purchases the copy. In many cases, the username-and-password paradigm also requires the user to identify herself repeatedly, rather than once, and is therefore overly intrusive, deterring user acceptance. Alternatively, a “cookie”— a small file controlled by the browser but accessible by the server— containing the user name and other information can be stored on the user's computer. Many users, however, resist cookies because of the potential invasion of privacy that results.
Physical media distribution, such as concerts, provides a comparative analogy. In general a concert attendee does not have to identify herself with a password to gain admission. Instead, anyone with a valid ticket is admitted. If a person with a valid ticket wishes to leave and re-enter, however, a hand stamp is used to identify the attendee as she leaves. Subsequently, only that person will be allowed to re-enter the event, which she may do as many times as she wishes. If, on the other hand, the attendee exits and gives her ticket stub to a friend whose hand is not stamped, the friend cannot enter.
In network media distribution, however, because two or more users may use the same username and password (in some systems simultaneously), current state of the art DRM systems do not effectively prevent multiple persons from “entering” the same event using one “ticket.” Yet, as noted above, they are intrusive in that they require the user to identify herself with name and password, sometimes multiple times, or require storing cookies on her computer, in order to gain access.
User validation methods for protection of media content are well known in the art. As previously stated, user validation is typically achieved by a combination of a username and a password. Other methods of user validation include using digital tickets that are punched once the consumer receives the digital work, e.g., see U.S. Pat. No. 6,236,971 titled “System for controlling the distribution and use of digital works using digital tickets.” While these methods provide content owners with some protection of their media content, they either fail to control the usage of the media file once it has been delivered to the consumer or fail to control the number of users who receive the same media content.
What is needed, therefore, is a mechanism that can be used in network media distribution to “hand-stamp” consumers' computers so that once the media content has been paid for, only one consumer will be allowed to receive it and play it, including receiving it and playing it multiple times, while at the same time avoiding intrusive and annoying username and password queries or other unattractive alternatives.